I'm trying to make length = 001 in Python 3 but whenever I try to print it out it truncates the value without the leading zeros (length = 1). How would I stop this happening without having to cast length to a string before printing it out?
5 Answers
Make use of the zfill() helper method to left-pad any string, integer or float with zeros; it's valid for both Python 2.x and Python 3.x.
It important to note that Python 2 is no longer supported.
Sample usage:
print(str(1).zfill(3))
# Expected output: 001
Description:
When applied to a value, zfill() returns a value left-padded with zeros when the length of the initial string value less than that of the applied width value, otherwise, the initial string value as is.
Syntax:
str(string).zfill(width)
# Where string represents a string, an integer or a float, and
# width, the desired length to left-pad.
Since python 3.6 you can use f-string :
>>> length = "1"
>>> print(f'length = {length:03}')
length = 100
>>> print(f'length = {length:>03}')
length = 001
4 Comments
bn_ln
Safer to use
print(f'length = {length:>03}') (note the >) as this example would fail if length were a string, eg. length = '1'
Thomas909
For large datasets, note that the top answer (zfill) is moderately faster than this method given an integer input and about 3x faster if your input is already formatted as a string.
Magnus Lind Oxlund
What's being used here is Python's formatting mini-language. Here's a cheat sheet with examples: gist.github.com/gauthamchettiar/…
winterlight
print(f'length = {length:>03}') failing for negative numbers. str(length).zfill(3) working still fine.There are many ways to achieve this but the easiest way in Python 3.6+, in my opinion, is this:
print(f"{1:03}")
answered Aug 4, 2019 at 17:06
Anatol Zakrividoroga
4,6282 gold badges36 silver badges57 bronze badges
4 Comments
Cherona
Could you please explain this syntax, or link where I may read more about it?
Anatol Zakrividoroga
dduffy
I find this the easiest method. The "3" part dictates the number total digits. so {1:03} would display 001. If it was {123:03} then it would display 123. If it was {123:04} then it would display 0123, etc...
Radamand
hey that really is the slickest way!
Python integers don't have an inherent length or number of significant digits. If you want them to print a specific way, you need to convert them to a string. There are several ways you can do so that let you specify things like padding characters and minimum lengths.
To pad with zeros to a minimum of three characters, try:
length = 1
print(format(length, '03'))
Comments
I suggest this ugly method but it works:
length = 1
lenghtafterpadding = 3
newlength = '0' * (lenghtafterpadding - len(str(length))) + str(length)
I came here to find a lighter solution than this one!
1 Comment
Anatol Zakrividoroga
try this:
print(f"{1:03}")
001.length = 001is the same aslength = 1' (number) and to get001` you should use some string formatting (see answers). Butlength = '001'is different, it's a string and you can get number viaint(length).